In what may be another signal that Facebook Inc. wants to take on YouTube, the company has reached out to some of the Google Inc.-owned video site's biggest content producers and encouraged them to test distributing their videos on the social network, say people familiar with the matter.

Already some YouTube content producers, including Walt Disney Co.'s Maker Studios and Collective Digital Studio, have experimented with putting some of their top YouTube series on Facebook. Collective has made available its animated viral...